Z270x Motherboard External Temp Sensors

Had my Z270x gaming 7 for a about a month now, running a 7700k oc'd @ 4.8ghz with a Nitro R9 390x & 16gb trident z RGB 3200mhz, powered by a HX850i, running sweet ! The board comes with two external temp sensors you can plug into ec_temp1 & ec_temp2, if i was to use them both what would be an ideal location for them to read temps? inside or outside the case? if inside the case, where abouts? if outside the case where abouts? just curious, hope someone can help..!